Evidence supports that it is, in fact, located just outside of Orlando, FL.
https://www.bbc.com/travel/article/20230212-a-city-under-the...
[NB This is based on me recognising the landscape in some of the movies, apparently the books say it is near Dufftown - which is on the other side of Scotland].
I had also assumed it was the school on Lauriston Place in Edinburgh, but apparently that's definitely not true...
https://www.pottertour.co.uk/blog/george-heriots-school-harr...
Mind you - I'm not really that big a Harry Potter fan but I did live in that part of Edinburgh for many years and my son went to Heriots after adventures at other schools...